Several medical conditions involve smooth muscle contraction and inflammation due to the effects of prostaglandins and other hormones produced within the body. Symptomatic relief has been achieved with naturally-occurring or synthetic small molecules. There has been little information about the use of herbal remedies for symptomatic relief.
The enzyme cyclooxygenase is rapidly induced upon exposure to agents such as hormones, cytokines and growth factors with the resulting formation of prostaglandins. COX starts a cascade of reactions which convert the fatty acid arachidonic acid to one of a group of prostaglandin molecules, a group of hormones that cause a number of effects such as maintaining smooth muscle tone, controlling the production of stomach acid and participation in inflammation and blood clotting. It is thought that prostaglandins are also direct pain signals. Among the many conditions that result from the action of prostaglandins are menstrual cramps, asthma, pain and inflammation. There are two varieties of cyclooxygenases, which are present in various tissues. COX-1 is considered to be important in controlling the production of stomach acid and the aggregation of platelets. Inhibition of COX-1 results in the increased production of stomach acid and reduces platelet aggregation; these combined effects may lead to stomach and duodenal ulcers and bleeding. COX-2 is considered to be important in controlling smooth muscle contraction, pain and inflammation. Inhibition of COX-2 results in reduction of cramping, pain and inflammation.
Dysmennorrhea is an exemplar condition. As many as 40 million women in the United States alone suffer from menstrual cramps with associated bloating, backache, fatigue, mood swings, excessive bleeding and nausea. These symptoms are caused by the hormonal fluctuations accompanying menstruation, when prostaglandins are produced in the uterine lining, causing uterine smooth muscle contractions, reducing blood flow and temporarily cutting off oxygen supply to the tissues. These contractions are felt as menstrual cramps. While most woman experience at least some cramping, in others higher than normal levels of prostaglandins cause severe menstrual cramps that are incapacitating. Whether mild or severe, women suffering from menstrual cramps seek relief.
Arthritis is a well-known inflammatory condition. Inflammation of the joints results in severe pain, deformation and inanition. Arthritis occurs either as a result of an immune-type inflammation (rheumatoid arthritis) or can result from wear and tear on the joints (osteoarthritis). The condition often progresses to the point where artificial joints are used to replace the arthritic joints.
Tumor Necrosis Factor-α (TNF-α) is a proinflammatory, multifunctional cytokine which is released by mast cells and macrophages in response to environmental triggers, and has been implicated in the pathophysiology of inflammatory diseases. Anti-TNF-α therapy has been approved to treat Crohn's disease and rheumatoid arthritis. A prevalent condition that is mediated by prostaglandins and TNF-α is asthma. The incidence of asthma is increasing worldwide. It is characterized by wheezing and shortness of breath, leading in some cases to respiratory failure and death. The production of prostaglandin in response to viral or bacterial infection, exercise, allergic or environmental stimuli such as cold or dehydration leads to contraction of the smooth muscles of the bronchi, causing obstruction of the airways. TNF-α release causes inflammation with bronchiolar edema and mucus production, which exacerbates the condition. Treatment for asthma is twofold: “rescue” drugs such as epinephrine (injected or inhaled) or albuterol are administered during an acute attack and are followed by maintenance therapy to reduce or eliminate the bronchospasm reaction. The most common maintenance therapy includes the avoidance of triggering factors such as animal or food allergies and anti-inflammatory drugs such as steroids. In recent years, additional maintenance drugs have been marketed which intervene at other points in an asthmatic attack.
There are many drugs available to treat inflammatory conditions. Aspirin, a drug used for more than 150 years, was the first synthetic drug used to treat pain. When it was discovered that aspirin acted by inhibiting prostaglandin synthesis, pharmaceutical manufacturers devised many other synthetic drugs that acted in the same manner, commonly termed NSAIDs (non-steroidal anti-inflammatory drugs). Among these are ibuprofen, naproxin and the so-called COX-2 inhibitors. The goal has been to inhibit COX-2 while minimizing COX-1 inhibition. While these drugs, like aspirin, are effective, they may cause side effects. Manufacturers of pain relievers spend millions of dollars in advertising to convince the public that these drugs are a safe and effective way to deal with headache, arthritis and menstrual cramps. In fact, however, more than 100,000 Americans were hospitalized each year from taking over-the-counter pain relievers, with about 20,000 deaths. The most common side effect is gastrointestinal distress with discomfort and bleeding, which can be severe. Less common side effects include drowsiness, confusion, kidney damage and liver damage.
Many persons prefer a natural, non-synthetic drug preparation to a synthetic drug. Herbal preparations offer an alternative to synthetic drugs. Dr. Duke's Phytochemical and Ethnobotanical Database (www.ars.grin.gov/duke) lists botanicals and references publications claiming activities which range from anti-inflammatory uses to anti-cancer treatments. Particularly, plants in the Lamiaceae “mint” family have been used for both their culinary and healthful properties. The mint family includes about 200 genera, such as Salvia (sage), Rosmarinus (rosemary), Mentha (mint), Ocimum (basil), Thymus (thyme), Marrubium (hoarhound), and Nepeta (catnip). Another family with useful properties is the Apiaceae (cumin) group.
The need remains to identify herbal preparations which will give relief from inflammatory conditions and smooth muscle contractions.